﻿//  Copyright 2019 Google Inc. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.

using NtCoreLib.Native.SafeHandles;
using NtCoreLib.Utilities.Reflection;
using System;
using System.Runtime.InteropServices;

namespace NtCoreLib;

#pragma warning disable 1591
[Flags]
public enum IoCompletionAccessRights : uint
{
    [SDKName("IO_COMPLETION_QUERY_STATE")]
    QueryState = 1,
    [SDKName("IO_COMPLETION_SET_COMPLETION")]
    SetCompletion = 2,
    [SDKName("GENERIC_READ")]
    GenericRead = GenericAccessRights.GenericRead,
    [SDKName("GENERIC_WRITE")]
    GenericWrite = GenericAccessRights.GenericWrite,
    [SDKName("GENERIC_EXECUTE")]
    GenericExecute = GenericAccessRights.GenericExecute,
    [SDKName("GENERIC_ALL")]
    GenericAll = GenericAccessRights.GenericAll,
    [SDKName("DELETE")]
    Delete = GenericAccessRights.Delete,
    [SDKName("READ_CONTROL")]
    ReadControl = GenericAccessRights.ReadControl,
    [SDKName("WRITE_DAC")]
    WriteDac = GenericAccessRights.WriteDac,
    [SDKName("WRITE_OWNER")]
    WriteOwner = GenericAccessRights.WriteOwner,
    [SDKName("SYNCHRONIZE")]
    Synchronize = GenericAccessRights.Synchronize,
    [SDKName("MAXIMUM_ALLOWED")]
    MaximumAllowed = GenericAccessRights.MaximumAllowed,
    [SDKName("ACCESS_SYSTEM_SECURITY")]
    AccessSystemSecurity = GenericAccessRights.AccessSystemSecurity
}

public enum IoCompletionInformationClass
{
    IoCompletionBasicInformation
}

[StructLayout(LayoutKind.Sequential)]
public struct FileIoCompletionInformation
{
    public IntPtr KeyContext;
    public IntPtr ApcContext;
    public IoStatusBlockStruct IoStatusBlock;
}

public class FileIoCompletionResult
{
    public IntPtr KeyContext { get; }
    public IntPtr ApcContext { get; }
    public IoStatusBlock IoStatusBlock { get; }

    internal FileIoCompletionResult(FileIoCompletionInformation result)
    {
        KeyContext = result.KeyContext;
        ApcContext = result.ApcContext;
        IoStatusBlock = new IoStatusBlock()
        {
            Information = result.IoStatusBlock.Information,
            Pointer = result.IoStatusBlock.Pointer
        };
    }

    internal FileIoCompletionResult(IntPtr key_context, IntPtr apc_context, IoStatusBlock io_status)
    {
        KeyContext = key_context;
        ApcContext = apc_context;
        IoStatusBlock = io_status;
    }

}

public struct IoCompletionBasicInformation
{
    public int Depth;
}

public static partial class NtSystemCalls
{
    [DllImport("ntdll.dll")]
    public static extern NtStatus NtCreateIoCompletion(
        out SafeKernelObjectHandle IoCompletionHandle,
        IoCompletionAccessRights DesiredAccess,
        [In] ObjectAttributes ObjectAttributes,
        int NumberOfConcurrentThreads
    );

    [DllImport("ntdll.dll")]
    public static extern NtStatus NtOpenIoCompletion(
        out SafeKernelObjectHandle IoCompletionHandle,
        IoCompletionAccessRights DesiredAccess,
        [In] ObjectAttributes ObjectAttributes
    );

    [DllImport("ntdll.dll")]
    public static extern NtStatus NtRemoveIoCompletion(
        SafeKernelObjectHandle IoCompletionHandle,
        out IntPtr KeyContext,
        out IntPtr ApcContext,
        [In, Out] IoStatusBlock IoStatusBlock,
        LargeInteger Timeout
    );

    [DllImport("ntdll.dll")]
    public static extern NtStatus NtRemoveIoCompletionEx(
        SafeKernelObjectHandle IoCompletionHandle,
        [Out] FileIoCompletionInformation[] IoCompletionInformation,
        int InformationCount,
        out int NumEntriesRemoved,
        [In] LargeInteger Timeout,
        bool Alertable
    );

    [DllImport("ntdll.dll")]
    public static extern NtStatus NtQueryIoCompletion(
        SafeKernelObjectHandle IoCompletionHandle,
        IoCompletionInformationClass IoCompletionInformationClass,
        SafeBuffer IoCompletionInformation,
        int IoCompletionInformationLength,
        out int ReturnLength
    );

    [DllImport("ntdll.dll")]
    public static extern NtStatus NtSetIoCompletion(
        SafeKernelObjectHandle IoCompletionHandle,
        IntPtr KeyContext,
        IntPtr ApcContext,
        NtStatus Status,
        IntPtr IoStatusInformation
    );

    [DllImport("ntdll.dll")]
    public static extern NtStatus NtSetIoCompletionEx(
        SafeKernelObjectHandle IoCompletionHandle,
        SafeKernelObjectHandle IoCompletionPacketHandle,
        IntPtr KeyContext,
        IntPtr ApcContext,
        NtStatus IoStatus,
        IntPtr IoStatusInformation
    );
}

#pragma warning restore 1591

